A Dictionary of Music and Musicians/Costanzi, Juan
COSTANZI, Juan, known as Gioannino di Roma, because he was born there; was for some time in the household of Cardinal Ottoboni, and was appointed in 1754 chapel-master of St. Peter's, which he retained till his death in 1778. He composed an opera 'Carlo Magno' (Rome 1729); a fine 'Miserere'; motets in 16 parts for 4 choirs, offertoriums, and other church music.
[ M. C. C. ]